The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in the present disclosure and are not admitted to be prior art by inclusion in this section.
Passive resistors used in many electronic circuits, such as analog, mixed-signal, and/or radio frequency circuits, are formed using poly, diffusion, or N-well resistors. Key attributes for passive resistors are linearity, temperature co-efficient, and variability. These passive resistors occupy significant active silicon area, and are typically enclosed in special layout structures (e.g., guard rings).